A three-toed woodpecker peeking out the tree cavity., Kim Melton
A three-toed woodpecker peeking out the tree cavity. © Kim Melton

Burning trees: not a good way to solve the climate crisis


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Donald Reid
Emeritus Scientist

Hilary Cooke
Co-Director, Northern Boreal Mountains Program

Related

Boreal Climate change Natural resource development

Published

2023-08-01

Letter to Yukon News: re Biomass for Institutional Heating

The Yukon Government wants to expand the use of wood (aka biomass) to fuel boilers used to heat large buildings, a plan detailed in its strategy for dealing with energy and climate change called “Our Clean Future.” For the last four years, Wildlife Conservation Society Canada scientists have voiced concerns about plans to increase use of wood to meet Yukon’s energy needs, while drawing attention to major flaws in the argument that such increased burning would be an effective climate solution.

One major concern is the source of this wood. In “Our Clean Future”, the government envisages a Yukon-based industry supplying wood for the 20 boiler systems that it intends to install or subsidize. In recent decades, most commercially harvested firewood in Yukon has been salvaged from burns or areas with beetle-killed trees, and those would seem to be the most likely sources of wood for the new boiler systems.

However, there are two big issues with this. First, fire- and beetle-killed trees are increasingly in short supply close to Whitehorse. We cannot “plan” a future supply of such deadwood within economically feasible transportation distances to the main markets (notably Whitehorse).

Second, standing or fallen fire- or beetle-killed trees are not waste wood. They are critical habitat for numerous boreal species that have evolved to depend on such disturbances. While the government has made a positive commitment in its review of the Forest Resources Act to manage harvest of dead wood differently from green wood, there is still a lot of work to be done on standards and regulations. To be ecologically sustainable, salvage logging must face constraints on what, how much, how, when, and where harvesting occurs.

As a result, we face a high risk that the government will permit green wood (standing live trees) harvesting to supply the biomass market it is trying to create. This controversial use of forests happens elsewhere, including in British Columbia and the U.S. In Yukon, new fire breaks will produce some green wood, but this could also supply existing residential heating demands and would not be sufficient to supply 20 new boiler installations over at least 20 years.

More widespread harvesting of green wood just for space heating would be a travesty. It would reduce the number and extent of mature trees that are at optimal age for ongoing carbon absorption from the atmosphere and would transfer the carbon in those trees into the atmosphere. It would put mature forest habitats for numerous species (notably caribou) at risk. It would degrade natural viewscapes prized by the tourism industry.

The government argues that biomass energy produces lower carbon emissions than fossil fuels. It has told us that this assumption is justified because the Intergovernmental Panel on Climate Change (IPCC) considers wood to be a “renewable” energy source (in the same category as solar and wind). IPCC sets the rules by which nations have to report their carbon emissions and has declared that renewables, including biomass, do not produce reportable emissions. So, in its accounting of carbon emissions, the Yukon government gets to claim a reduction by replacing propane (fossil fuel) with wood (renewable), no matter what emissions come from burning wood.

The flaw in the IPCC rules has been repeatedly critiqued internationally by scientists, policy analysts, and some politicians, but continues to be a green-washing shield behind which many jurisdictions hide. Australia recently addressed the flaw by declaring that biomass would no longer be classified as “renewable.”

In the real world of atmospheric physics and chemistry, it takes many decades for young trees to absorb all the carbon lost by burning mature trees in any one winter, no matter the efficiency of the burning. On paper, the government can state that it has reduced emissions. In reality, those emissions will largely continue, at levels that depend on the quality of the wood and how the boiler systems are operated. Also, any harvesting of green wood would produce new carbon emissions that would negate some of the emissions reductions the government claims by replacing fossil fuels with biomass. In fact, the government would be obliged to report these new emissions from clearing forests in its annual accounting under the IPCC rules.

It's important to also note that the new boiler systems commit us to burning wood for at least two decades, thereby pushing the real carbon accounting (including new tree growth) far beyond 2050, by which point Yukon is supposed to be “zero-carbon.”

Overall, we are very skeptical that increasing the use of wood for institutional space heating will be of any significant or real benefit in mitigating climate change. Instead, the government needs to put more effort into truly low-carbon energy sources, such as wind, solar and micro-hydro that do not perpetually produce emissions. It also needs to encourage more energy efficient heating systems, such as air-source and ground-source heat pumps (which can cut emissions significantly even in Yukon’s cold climate).

Using biomass instead poses a serious threat to the conservation of Yukon’s ecosystems. Combined with questions raised by others about the economics and simple feasibility of using biomass, we think the case for using wood-fired boilers is weak at best and a climate deception at worse.

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